Pin core structure for decreased checking



Feb- 1, 1966 F. E. sATcHr-:LL ETAL. 3,232,617

PIN CORE STRUCTURE FOR DECREASED CHECKING INVENTORS. @M m Filed 001:. l5, 1962 United States Patent C 3,232,617 PIN CGRE STRUCTURE FOR DECREASED CHECKING Fred E. Satchell, and Foster W. Berry, Muskegon, Mich., ssgnors to Brunswick Corporation, a corporation of e aware Filed Oct. 15, 1962, Ser. No. 230,476 s Claims. (C1. 273-82) This invention relates to bowling pins and more particularly relates to preventing or inhibiting neck checking in wood core bowling pins.

Bowling pins used in such games as ten pins and duck pins are subjected during use to high stresses generated by impact by a bowling ball with the pin. Such high stresses are particularly prominent at or just below the minimum section of the pin, i.e., in the neck region of the pin. The high stresses, together with the natural configuration of the tissue elements of a wood core, may often result in checking or failure in the wood core parallel to the wood grains. Such checking may be engendered by repeated impact during use of the pin, or even by a single hard blow. Such checking may occur almost anywhere along the length of the pin although the neck section, especially at or below the minimum diameter of the pin, is often the most vulnerable site for check origination. Once the checks or splitting failures have been started in a pin, their growth or extension into other parts of the pin results in complete failure of the pin. Failure of pins due to checking is currently a serious problem and constitutes a prominent cause of shortened pin life.

It is a general object of this invention to provide a new and useful bowling pin having reduced checking tendencies.

More particularly, it is an object of this invention to provide a new and useful bowling pin including an internal elastic or elastomeric material, especially in the neck region of the pin, which serves to reduce the -tendency of check formation in the outer wood surface of the pin core.

It is a further object of this invention to provideva bowling pin which has a core structure including a plurality of wood portions and a substantially internal elastic body of elastic material between the wood portions, at least in the neck section of the pin.

It is another object of this invention to provide such a bowling pin wherein the wood portions of the neck region of the pin include a plurality of separate hardwood portions bonded to a continuous substantially internal elastic matrix of elastomeric material having a substantially lower modulus of elasticity than the modulus of elasticity of the hardwood. v

In one embodiment of the present invention there is provided a bowling pin in accordance with the foregoing objects in which the core consists essentially of a plurality of elongated wood blocks with the matrix or elastomeric material interposed therebetween, the blocks and matrix extending the length of the wood core.

In still another embodiment of this invention there is provided a bowling pin in accordance with the above objects wherein the wood portions of the core comprise a base-belly-shoulder portion having a receptacle in its upper surface and a head-neck portion having a projection from its lower surface, the projection being received within the receptacle and spaced from the walls of the receptacle and the internal matrix of elastomeric material being coincident with the space between the projection and the walls of the receptacle.

Other objects and embodiments, including the use of a synthetic rubber material such as thiokol rubber as the elastic or elastomeric material, the use of particular thicknesses of such elastic or elastomeric material, and

3,232,617 Patented Feb. 1, 1966 ICC still other objects will be apparent from the following descriptions and drawings n which:

FIG. l is a vertical section of an embodiment of the bowling pin of this invention, corresponding to avsection taken along lines 1-1 of FIG. 2;

FIG. 2 is a horizontal section through the embodiment illustrated in FIG. l along lines 2 2 of FIG. 1;

FIG. 3 is a vertical section through another embodiment of the bowling pin of this invention; and

FIG. 4 is a horizontal section through the embodiment illustrated in FIG. 3 taken along lines 4 4 of FIG. 3.

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail an embodiment of the invention together with a modification thereof with the understanding that the present -disclosure is to be construed as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. The scope of the invention will be pointed out in the appended claims.

Referring first to FIGS. 1 and 2 of the drawings there is illustrated an embodiment of the bowling pin of the present invention. Pin core 10 is formed of laminated maple blocks 11, 12, 13 and 14, elongated maple blocks lettered a through r, and a thiokol rubber longitudinal elastic member or matrix 15. Although the longitudinal matrix illustrated includes, in the horizontal cross-sectional view of FIG. 2, individual element thicknesses of 1A to 3/s inch effectively extending substantially across the core, other thicknesses and configurations in the Inatrix may be used as will be apparent. Blocks a through r are bonded to matrix 15. Additionally the peripheral blocks of the plurality of elongated blocks a through r are laminated to blocks 11, 12, 13 and 14 in the core structure. Matrix 15 is bonded to all wood blocks in contact therewith. An ethylcellulose lacquer coating 16 is provided on the exterior of core Il) and the coated core comprises a regulation size ten pins bowling pin. Of course, other adaptations such as an impact resistant base may be incorporated in the illustrated pin.

Although the pin core is described as formed of laminated maple blocks, other woods, and especially other hardwoods, may be used. Also, other coating materials, either in combination with or in lieu of ethylcellulose, may be used, including nitrocellulose, cellulose acetate, cellulose acetate and butylate, epoxies, urethanes, and the like. Such coating materials are well known to those in the art.

Referring now to FIGS. 3 and 4, there is illustrated another embodiment of the present invention. In FIGS. 3

and 4, core 20 is constructed of an upper or cap-head? neck portion 21 and a lower or base-belly-shoulder portion 22. Upper portion 21 includes projection 23 at the lower end thereof and lower portion 22 includes receptacle 24 at the upper end thereof. Projection 23 and receptacle 24 are positioned in spaced relation to each other, i.e., the walls of receptacle 24 being spaced from the walls of projection 23. Filling the space between projection 23 and receptacle 24 is a thiokol rubber transverse member or cup 25 which has a wall and bottom thickness, as illustrated, of about 1A to 1/2 inch. Acoating 26 of ethylcellulose or other coating material is provided on the surface of core 20. p

Although the embodiments of FIGS. l through 4 have been described as employing thiokol rubber as the elastic material, it is to be understood that other materials which are highly elastic may be used. The elastic material of the internal elastic body of the bowling pin of this invention has a substantially lower modulus of elasticity than that of the wood of the core. Both natural and synthetic rubber-like materials are usable, for example, including natural rubber, chemically resistant rubber such as thiokol or polysullide rubber, copolymers of styrene and butadiene such as GR-S rubber, polybutadienes such as Buna rubber, cold-ow rubber (polyisobutylene), butyl rubber (a copolymer of isobutylene with small amounts of butad-iene), polychloroprene such as neoprene, silicone rubber (eg. polydimethylsilanediol), polyurethane rubber, and the like. The elastic or elastomeric material has a lower tensile strength than that of the wood of the core. Any elastic or rubber-like material is usable.

The elastic material can be used in any configuration within the wood core pin when viewed in horizontal section, c g. triangular, parallel line, circular, radial, etc., configuration. The location of the elastic material is not critical so long as it constitutes an elastic body of material separating a plurality of, i.e. at least two, pieces of wood in the core. It is preferred, however, that the elastic material be sufficiently toward the center of the pin at the belly portion of the pin, if it is present at the belly portion, to permit sufficient circumferential wood at the belly to maintain good playing characteristics.

The thickness of the elastic material depends somewhat on the elasticity of the material. As the elasticity of the material increases, it can be used in lesser thicknesses. For more advantageous use of elastic materials, the individual elements of elastic material in the core should be at least 5 to l() mils in thickness even where very soft and elastic materials are used. When using the soft and yielding materials of soft rubber consistency, it is preferred that they be included in the core of the pin in a thickness of at least about 60 mils.

Although, as indicated above, one elastic element may be provided between two wood core members in accordance herewith, because the elastic elements are free to de llect in shearincreasing their number gives a greater cushioning effect to the pin core, thus, cushioning depends on at least the elasticity of the material and the thickness and number of elastic elements. The cushioning effect is accordingly adjustable by increasing the elasticity and/ or thickness or number of elastic elements used to increase cushioning, or by decreasing the elasticity and/ or thickness or number of elements to decrease the cushioning effect. This permits adjusting of the cushioning elfect in both directions so that checking ofthe core may be lessened or prevented; but if the resulting cushioning effect of a certain elastic-material or thickness of material in a givenpin construction results in an undesirably overcushioned or sound -deadened pin, the cushioningeffeci may be readjusted in subsequently produced pins of that construction to regain at least some of the sound characteristics.

The maufacture of bowling pins in accordance herewith includes generally the lamination-and shapingof a wood core containing the elastic member and thereafter coating.

the shaped core. The elastic member may be included in the core by introducing the elastic materialin a liquid state, i.e. molten, plasticized, unpolymerized or as a soluf tion into the spaces between .the wood core elements. Accordingly, a bowling pin of the conligurationvof that in FIG. l can be formed by iirst forming a mold cavity by laminating blocks 1l, 12, 13 and i4 together, supporting blocks av through r. within the cavityand pouring liquid elastic material, eg. thiokol rubber, into the cavity surfrounding the Velongated wood blocks. The elastic material is then cured in place. For curing, some elastic materials may Vrequire heat and/ or pressure and because of the difficulties in applying pressure .to the mold `cavity it is -preferredthat the elastic material be one curable without/application of pressure.

In like manner, a pin of the configuration illustratedvin FIGS. 3 .and 4 may be made by turning blocks 21 and 222 separately, placing thiokol rubber within cupy 24, and: inserting projection 23V into cup4 24 causing the thiokol rubber to flow upward and ll the space between projection 23andthe walls -of cup 24;. Thereafter, the thiokol rubber is cured. Ineither case the woodfblocks may be preshaped, if desired, or preferably Vthe resulting built-up core is shaped to its proper size and configuration for coating to form a finished bowling pin.

Alternatively, the elastic body may be molded separately from the pin, e.g, in theshape of longitudinal member 15 or ltransverse member 2S, and thereafter laminated between the respective wood portions of the pins using a suitable adhesive material. Suitable adhesive materials are well known to those in the art; for example, an epoxy resin adhesive may be used to bond a molded thiokol rubber elastic member to maple wood .portions of the bowling pin core. i

After the core has been formed, the coating material is applied by any of a variety of well known processes including dipping, brushing, owing, etc.

It is evident from the foregoing that the present invention provides new and useful bowling pins which may in clude apredominately wood core with a substantially internal elastic body of material between wood portions of the core. The pins provided in accordance herewith, when subjected to normal bowling use, are less susceptible to neck .checking than are the wood core bowling pins not including the elastic body. Such prevention or inhibition of neck checking in bowling pins often results in extended playing life of the pins, reducing the frequency of their replacement. Y

We claim:

l. A bowling pin comprising an upper wood portion, a lower wood portion and a transverse continuous s ubstantially internal elastic body of elastic material between said upper and lower portions and bonding said upper and lower portions, said transverse body being between the largest and smallest diameters of said pin, said elastic material'being of sutiicient Vmass to decrease checking of the surface wood inthe neck of the pin normally caused by impact at the bellyof the pin.

2. A bowling pin comprising a predominantly wood core having a neck portion consisting,essentiallyV of a plurality of separate hardwood portions bonded to a continuous substantially internal elastic matrix of elastomeric material having a substantially lower modulus of elasticity than said wood, said wood portions` comprising a base, belly and shoulder portion having a receptacle in its upper surface and ahead and neck portion having a projectionffrom its lower surface received within said receptacle in spaced relation to thewalls of said .receptacle and said internal matrix being coincident with the space between said projection and the walls of said receptacle.

3. A bowling pin having a core including a neck portion and a belly portion and comprising a plurality of wood portions and a substantially internal elastic body of elastic material extending the length of said core between said wood portions for absorbing sucient shock to reduce neck checking in the pin under impact of the pin in the belly portion by a bowling ball.

4. A bowlingpin having a predominantlywood core including a neck portion and a belly'portion and comprising a plurality of elongatedseparate hardwood portions andv acontinuous substantially internal elastic matrix-of elastomeric material extending thelength of the core for absorbing suliicient shock to reduce neck checking inthe pin under impact. of the pin in the belly portion by a bowling ball and for bonding said hardwood portions in spaced relation, said elastomeric material having a substantially lower modulus of elasticity than the wood.

5,. A bowling pin having a solid core comprising a plurality of `spaced separate elongate WODC! blocks each extending the length of the core and a continuous4 subs tantially yinternal elastic body of elastic materialhaying a substantially lower modulus of elasticity than that of said wood, said internal body of elastic material extending the length of the core and being of a thickness greater than about 5-10 mil-s for lpermitting flexure of said .wood blocks relative to each other and absorbing suiiicient shock from .impacts inthe' belly portion of the core by a 5 bowling ball to reduce neck checking in the pin, said 2,878,021 core including an amount of Wood sucient to maintain 2,968,485 the playing sound characteristics of a Wood pin, and said Wood blocks being bonded and held by said elastic body of elastic material. 5 3,123 6,630 References Cited by the Examiner 3 3g() /31 UNITED STATES PATENTS 2,517,116 8/1950 Klinger 273-82 2,568,274

2,809,038 10/ 1957 Scheidemantel et al. 273-82 3/1959 Lippert 273-82 1/1961 Alcr 273-82 FOREIGN PATENTS 1890 Great Britain.

1896 Great Britain. 7/ 1932 Australia.

RICHARD C. PINKHAM, Primary Examiner. 9/1951 Clark 273-82 X 10 DELBERT B. LOWE, Examiner. 

1. A BOWLING PIN COMPRISING AN UPPER WOOD PORTION, A LOWER WOOD PORTION AND A TRANSVERSE CONTINUOUS SUBSTANTIALLY INTERNAL ELASTIC BODY OF ELASTIC MATERIAL BETWEEN SAID UPPER AND LOWER PORTIONS AND BOUNDING SAID UPPER AND LOWER PORTIONS, SAID TRANSVERSE BODY BEING BETWEEN THE LARGEST AND SMALLEST DIAMETERS OF SAID PIN, SAID ELASTIC MATERIAL BEING OF SUFFICIENT MASS TO DECREASE CHECKING OF THE SURFACE WOOD IN THE NECK OF THE PIN NORMALLY CAUSED BY IMPACT AT THE BELLY OF THE PIN.
 4. A BOWLING PIN HAVING A PREDOMINANTLY WOOD CORE INCLUDING A NECK PORTION AND A BELLY PORTION AND COMPRISING A PLURALITY OF ELONGATED SEPARATE HARDWOOD PORTIONS AND CONTINUOUS SUBSTANTIALLY INTERNAL ELASTIC MATRIX OF ELASTOMERIC MATERIAL EXTENDING THE LENGTH OF THE CORE FOR ABSORBING SUFFICIENT SHOCK TO REDUCE NECK CHECKING IN THE PIN UNDER IMPACT OF THE PIN IN THE BELLY PORTION BY A BOWLING BALL AND FOR BONDING SAID HARDWOOD PORTIONS IN SPACED RELATION, SAID ELASTOMERIC MATERIAL HAVING A SUBSTANTIALLY LOWER MODULUS OF ELASTICALLY THAN THE WOOD. 